BSA B50 -500 APG Build

[Jack Gifford]

... figure out an easy way to back off the pucks...

Every now and then the rear caliper on my Guzzi V50 starts to drag. I now carry a T-handle Allen wrench to quickly loosen the two mounting bolts and push the caliper side-to-side a little, then tighten the bolts; takes about a minute and then I'm good for another few hundred miles. Would something like that work for you? [Yeah, I should replace the old high-mileage parts]

[Koncretekid]

Thanks Salt and Jack,
Firstly, the caliper came from a salvage yard where it had probably been setting for a long time and may have a little corrosion on the piston.  Secondly, I'm sure the old square O-ring may be a little stiff.  So rebuilding the caliper is the next step.  However, even a slight drag is not a good thing as it may create heat and get worse.  I can push the caliper with my fingers to loosen the pucks, but I can't get to it with the real wheel fully enclosed in the fairing.  Jim L. had a good suggestion about fastening a steel tube to the inside of the fairing which would direct a screwdriver like tool with a very thin blade to wedge the puck away from the disc, which I will try to do when I get back to N.S.
Tom

[JimL]

Just a note:  I was taught to disassemble old calipers and pistons and seals in a bucket of hot, soapy water.  Drop the caliper into the hottest water you can work in.  Anything to do with brake fluid is water soluble in some manner, even the rust.

[wobblywalrus]

Tom, a rebuilt caliper in good condition should have seals that retract the pistons a little bit like Jack says.  Sometimes it is hard to get them to do that.  In the past I have put springs on the pins between the pucks to spread them apart.  A problem was, they spread them apart too far.  Then, I took the springs out and fit little pieces of rubber oil line on the pins.  The segments were just long enough to spread the calipers a little bit.  That worked.  The ultimate and final solution I did was to fit new seals and stainless steel pucks.

[desperate]

Hi Tom, just started reading this, it's good stuff. We have a few things in common, I'm in my sixties & will be at Speed Week this year with my blown Indian Scout. I also live just outside Yarmouth.....in the UK! And finally, I've used wood many times to "Mock up" my frames. I worked out the length of mine by laying on the floor with a tape measure nipped between my toes. When I did the mock-up it was too long & had to be shortened 7". Saved a lot of time & money. Best of luck with everything. Chris.

[Koncretekid]

Just a note:  I was taught to disassemble old calipers and pistons and seals in a bucket of hot, soapy water.  Drop the caliper into the hottest water you can work in.  Anything to do with brake fluid is water soluble in some manner, even the rust.

I've ordered the basic rebuild kit and I'll follow your advice, including some way to retract the pucks.  Thanks.

Tom, a rebuilt caliper in good condition should have seals that retract the pistons a little bit like Jack says.  Sometimes it is hard to get them to do that.  In the past I have put springs on the pins between the pucks to spread them apart.  A problem was, they spread them apart too far.  Then, I took the springs out and fit little pieces of rubber oil line on the pins.  The segments were just long enough to spread the calipers a little bit.  That worked.  The ultimate and final solution I did was to fit new seals and stainless steel pucks.

Bo,
I've heard of the rubber tubing between the pucks and I like that idea.

Hi Tom, just started reading this, it's good stuff. We have a few things in common, I'm in my sixties & will be at Speed Week this year with my blown Indian Scout. I also live just outside Yarmouth.....in the UK! And finally, I've used wood many times to "Mock up" my frames. I worked out the length of mine by laying on the floor with a tape measure nipped between my toes. When I did the mock-up it was too long & had to be shortened 7". Saved a lot of time & money. Best of luck with everything. Chris.

Chris,
I won't be at Speedweeks although I would desperately like to.  My schedule doesn't allow me to get back to Colorado and on to Utah until later in the month so I attend the Bonneville Motorcycle Speed Trials at the end of August.

So many great machines to see; so little time left to do so!

Tom

[Koncretekid]

I picked up a "new" master cylinder with remote reservoir from China cheaper than I could get a used one, mounted it with a stainless steel hose from the master to the caliper, and it works fine but the piston doesn't retract fully.  I rebuilt the caliper but I still get drag.  So I made a tool to retract the piston from a piece of 1 1/4" tubing that encircles the banjo bolt.  Pushing on it forces the piston back into the caliper, then pulling on it slightly creates the clearance I need. Only drawback is that I have to pump the handle 2 or 3 times to get the brake back.  This should be OK unless a moose runs out in front of me at Loring next weekend, in which case they don't make brakes good enough to save me anyway.
I sent the rotor down to the only machinist in town capable of grinding it in hopes that the reground rotor won't need as much pushing & pulling to get clearance.

I also had to bore a hole in the rear fairing to access the caliper with the new tool or I would have to remove the rear fairings to do so.

Looking forward to next weekend, although I haven't done much to the motor this year.  Changed the timing a bit and I'm going to try the ram air airbox again with all the vents hooked up to the airbox.  I found out I have to seal off the keyhole in the gas filler cap to seal off the tank, which is also vented to the airbox.

Tom

[saltwheels262]

Good luck, Tom. Belated happy birthday, yesterday(?).

[Koncretekid]

Good luck, Tom. Belated happy birthday, yesterday(?).

Thanks, Bill, and we had decent luck. I just returned from Loring last night. I tried the ram-air system again, but it did not work. I removed it and on Sunday I set a new personal best record of 151.6 mph! The interesting thing was that I gained about 11 mph from the mile to the mile-and-a-half, so the bike was apparently still accelerating. Bonneville should be interesting as I'll have another half mile to get up to speed........if we get there at all.

You will be interested to know that Jimbo and "Junkyard Hog" Don R. set new personal bests as well, but I will let them update you on that.

Tom

[saltwheels262]

Well, you did pretty good .

Actually I listened to the broadcast for about 5 minutes and it just happen to be for Jimbo's 194 run.

Heard from both of them yesterday.

Franey

[fordboy628]

Good luck, Tom. Belated happy birthday, yesterday(?).

Thanks, Bill, and we had decent luck. I just returned from Loring last night. I tried the ram-air system again, but it did not work. I removed it and on Sunday I set a new personal best record of 151.6 mph! The interesting thing was that I gained about 11 mph from the mile to the mile-and-a-half, so the bike was apparently still accelerating. Bonneville should be interesting as I'll have another half mile to get up to speed........if we get there at all.

You will be interested to know that Jimbo and "Junkyard Hog" Don R. set new personal bests as well, but I will let them update you on that.

Tom

Way to go Tom!!!!!

Congrats!!!!!

[Frank06]

Tom, congratulations on the 151.  I was at the mile and you looked and sounded smooth and steady.  Very nice!

[Marty]

These are my 2 cents about slight drag on calipers. There are 2 tricks I use. One being that I back off the mounting bolts 1 full turn then safety wire both bolts. the other is on dual caliper style, I use springs on the pad mounting poles. This will reduce drag as well. However I do this on my Dragbike for 1/4 mile sprints, but works well.

[Old Scrambler]

WOW

151 is in the 650-twin domain

I'm having my own struggles trying to get ram-air installed...........

[wobblywalrus]

That is a good speed, Tom.